Re: raid10 redundancy

On 5/13/21 11:38 AM, Phillip Susi wrote:

Roy Sigurd Karlsbakk writes:

quoted

Basically, the reason to use raid10 over raid6 is to increase
performance. This is particularly important regarding rebuild
times. If you have a huge raid-6 array with large drives, it'll take a
long time to rebuild it after a disk fails. With raid10, this is far
lower, since you don't need to rewrite and compute so
much. Personally, I'd choose raid6 over raid10 in most setups unless I

How do you figure that?  Sure, raid6 is going to use more CPU time but
that isn't going to be a bottleneck unless you are using some blazing
fast NVME drives.  Certainly with HDD the rebuild time is simply how
long it takes to write all of the data to the new disk, so it's going to
be the same either way.

No, rebuild isn't just writing to the new disk.  You have to read other disks to get the data to write.  In raid6, you must read at least n-2 drives, compute, then write.  In raid10, you just read the other drive (or one of the other drives when copies>2), then write.

Phil